The invention relates to the field of turbogenerators, and more particularly to an improved high speed turbogenerator that is constructed with an electrical generator normally employed in aerospace applications by adding to that generator, an expander wheel of a particular configuration and in which the entire high speed turbogenerator is contained within a conduit having a venturi or restriction in the conduit such that gas flowing through the conduit is directed through the radial inflow expander to turn the same for operating the electrical generator to derive power.
There have been numerous attempts in the past to adapt an electrical generator to be fitted within a conduit carrying a fluid, the objective being to derive energy from the fluid as it passes through the conduit and to thus convert that energy into a useful form.
One of the difficulties, however, is that the integrity of the conduit itself must, of necessity, be breached in order to convey that energy in some form outside the conduit. Various rotameters have been used inside conduits and geared to electrical generators outside the conduit, or other means have included inserting an electrical rotor within the conduit with a station or other excitation means outside the conduit and surrounding the same.
The disadvantages of the former means is obvious from the integrity standpoint of the conduit, i.e., larger openings must be cut into the wall of the conduit and thus special seals must be developed and utilized to prevent the fluid within the conduit from leaking to the outside environment. This is particularly a problem where that fluid is a combustible product such as natural gas.
The latter solution does alleviate the integrity problem but the efficiency of interposing a conduit wall between the rotary part of the generator and the starter causes a great reduction in efficiency of the the overall electrical generation capabilities.